The present invention relates to a series of new thienopyrimidine derivatives which have valuable insecticidal and acaricidal activities and also provides processes for preparing these derivatives and compositions containing them as the active ingredient.
Insects and acarids cause considerable damage to plants and can represent a serious danger to health; at best, they are a major nuisance. Accordingly, large sums are spent to destroy or deter them. Although many insecticides and acaricides are available, a large number of these have to be used with care, because they can endanger animals or because of their phytotoxicity. Moreover, because insects and acarids have short life cycles, they can develop immunity to many of the commonly used insecticides and acaricides, and accordingly, there is always a continuing need for new compounds exhibiting insecticidal and acaricidal properties.
A series of thienopyrimidine derivatives, which are said to have a variety of biological activities, including fungicidal, bactericidal, anti-viral, insecticidal, acaricidal and plant growth regulatory activities, is disclosed in British patent specification No. 2,043,061. These compounds may be represented by the formula: ##STR2## in which R represents an alkylene group optionally having a hydroxy substituent; Q represents a hydrogen atom, a phenyl group, a cycloalkyl group or an alkyl group optionally having one or more halogen, alkoxy or alkoxyalkoxy substituents; and X represents an oxygen or sulphur atom or a sulphonyl group. However, the biological activities of these compounds are not sufficiently high for them to be of practical, commercial use.
We have now discovered that a limited class of compounds similar to certain of those described in U.K. patent specification No. 2,043,061 has substantially more potent insecticidal and acaricidal activities than do the prior compounds and that the compounds, in addition to having such activity against insects and acarids of agricultural importance, are also effective against a variety of domestic insect pests, including flies, such as the housefly or mosquito.